When you receive a midi file from my email list that was recorded in a TYros Keyboard, you are not going to hear the original song unless you play it in a Tyros Keyboard. A midi file has no sounds in it. It has only pointers that point to the sounds in whatever device you are playing it in. When you play it back in a different device then the one it was created in, then it points to the closest sound available in the playing device sound card.
The tyros has 1000 plus instruments in it. A midi sound card has 128 instruments in it. So you can see the same instrument that was used to create the song may not be the instrument that you hear on playback, especially if you play it in your computer or a different keyboard. I hope this helps some of you to understand why midi songs don't always sound right to you.
Wav files and compressed wav files like MP3 have the original instrument sounds included in the file.